Triterpenoids and lignans from the stems of Schisandra glaucescens

Two new triterpenoids, 24(E)-3α,12α-dihydroxyl-lanost-9(11),24-dien-26-oid acid (1) and 3,4-seco-24(Z)-6α,7β-dihydroxyl-cycloart-4(28),24-dien-3,26-dioic-3-methyl ester (2), and ten known ones (3–12), together with eight lignans (13–20), were isolated from the stems of Schisandra glaucescens. Their structures were established on the basis of extensive spectroscopic analyses. Compounds 1–3, 5–7, 9, 11–13 and 15–18 were isolated from this species for the first time. 1 and 2 were evaluated for their in vitro cytotoxicities against the mouse cancer B16 cell line, human cancer HepG2 and MCF7 cell lines by MTT assay.     

Triterpenoids from the Stems of Schisandra glaucescens

Two new lanostane triterpenoids, schiglauzic acid ( 1 ) and schiglaucyclozic acid ( 2 ), together with two known ones, anwuweizic acid ( 3 ) and manwuweizic acid ( 4 ), were isolated from the stems of Schisandra glaucescens. Their structures were determined on the basis of extensive spectroscopic methods, including two‐dimensional NMR techniques, and were further confirmed by X‐ray crystallographic analysis.     

Antileishmanial Activities of Medicinal Herbs and Phytochemicals In Vitro and In Vivo: An Update for the Years 2015 to 2021

Leishmaniasis is one of the most neglected tropical diseases that present areal public health problems worldwide. Chemotherapy has several limitations such as toxic side effects, high costs, frequent relapses, the development of resistance, and the requirement for long-term treatment. Effective vaccines or drugs to prevent or cure the disease are not available yet. Therefore, it is important to dissect antileishmanial molecules that present selective efficacy and tolerable safety. Several studies revealed the antileishmanial activity of medicinal plants. Several organic extracts/essential oils and isolated natural compounds have been tested for their antileishmanial activities. Therefore, the aim of this review is to update and summarize the investigations that have been undertaken on the antileishmanial activity of medicinal plants and natural compounds derived, rom plants from January 2015 to December 2021. In this review, 94 plant species distributed in 39 families have been identified with antileishmanial activities. The leaves were the most commonly used plant part (49.5%) followed by stem bark, root, and whole plant (21.9%, 6.6%, and 5.4%, respectively). Other plant parts contributed less (<5%). The activity was reported against amastigotes and/or promastigotes of different species (L. infantum, L. tropica, L. major, L. amazonensis, L. aethiopica, L. donovani, L. braziliensis, L. panamensis, L. guyanensis, and L. mexicana). Most studies (84.2%) were carried out in vitro, and the others (15.8%) were performed in vivo. The IC₅₀ values of 103 plant extracts determined in vitro were in a range of 0.88 µg/mL (polar fraction of dichloromethane extract of Boswellia serrata) to 98 µg/mL (petroleum ether extract of Murraya koenigii). Among the 15 plant extracts studied in vivo, the hydroalcoholic leaf extract of Solanum havanense reduced parasites by 93.6% in cutaneous leishmaniasis. Voacamine extracted from Tabernaemontana divaricata reduced hepatic parasitism by ≈30 times and splenic parasitism by ≈15 times in visceral leishmaniasis. Regarding cytotoxicity, 32.4% of the tested plant extracts against various Leishmania species have a selectivity index higher than 10. For isolated compounds, 49 natural compounds have been reported with anti-Leishmania activities against amastigotes and/or promastigotes of different species (L. infantum, L. major, L. amazonensis, L. donovani and L. braziliensis). The IC₅₀ values were in a range of 0.2 µg/mL (colchicoside against promastigotes of L. major) to 42.4 µg/mL (dehydrodieuginol against promastigotes of L. amazonensis). In conclusion, there are numerous medicinal plants and natural compounds with strong effects (IC₅₀ < 100 µg/mL) against different Leishmania species under in vitro and in vivo conditions with good selectivity indices (SI > 10). These plants and compounds may be promising sources for the development of new drugs against leishmaniasis and should be investigated in randomized clinical trials.     

Organoboron Compounds: Effective Antibacterial and Antiparasitic Agents

The unique electron deficiency and coordination property of boron led to a wide range of applications in chemistry, energy research, materials science and the life sciences. The use of boron-containing compounds as pharmaceutical agents has a long history, and recent developments have produced encouraging strides. Boron agents have been used for both radiotherapy and chemotherapy. In radiotherapy, boron neutron capture therapy (BNCT) has been investigated to treat various types of tumors, such as glioblastoma multiforme (GBM) of brain, head and neck tumors, etc. Boron agents playing essential roles in such treatments and other well-established areas have been discussed elsewhere. Organoboron compounds used to treat various diseases besides tumor treatments through BNCT technology have also marked an important milestone. Following the clinical introduction of bortezomib as an anti-cancer agent, benzoxaborole drugs, tavaborole and crisaborole, have been approved for clinical use in the treatments of onychomycosis and atopic dermatitis. Some heterocyclic organoboron compounds represent potentially promising candidates for anti-infective drugs. This review highlights the clinical applications and perspectives of organoboron compounds with the natural boron atoms in disease treatments without neutron irradiation. The main topic focuses on the therapeutic applications of organoboron compounds in the diseases of tuberculosis and antifungal activity, malaria, neglected tropical diseases and cryptosporidiosis and toxoplasmosis.     

反相高效液相色谱法同时测定沙棘叶中绿原酸和芦丁

建立了同时测定沙棘叶中绿原酸和芦丁含量的反相高效液相色谱(RP-HPLC)法.采用Kromasil C18色谱柱(150×4.6mm,5μm),流动相为体积比20∶80的乙腈-1％乙酸水溶液,检测波长358 nm.结果表明:绿原酸、芦丁的浓度分别在0.0284～0.1704mg·mL-1(r =0.9995)和0.0566～0.3396mg·mL-1(r =0.9992)范围内与色谱峰面积呈良好线性关系;平均加标回收率分别为100.5％(n=5)和98.5％(n=5).该方法快速、准确,重现性好,可用于同时测定沙棘叶中绿原酸和芦丁含量.     

Six New Phenylpropanoid Derivatives from Chemically Converted Extract of Alpinia galanga (L.) and Their Antiparasitic Activities

Chemical conversion of the extract of natural resources is a very attractive way to expand the chemical space to discover bioactive compounds. In order to search for new medicines to treat parasitic diseases that cause high morbidity and mortality in affected countries in the world, the ethyl acetate extract from the rhizome of Alpinia galanga (L.) has been chemically converted by epoxidation using dioxirane generated in situ. The biological activity of chemically converted extract (CCE) of A. galanga (L.) significantly increased the activity against Leishmania major up to 82.6 ± 6.2 % at 25 μg/mL (whereas 2.7 ± 0.8% for the original extract). By bioassay-guided fractionation, new phenylpropanoids (1–6) and four known compounds, hydroquinone (7), 4-hydroxy(4-hydroxyphenyl)methoxy)benzaldehyde (8), isocoumarin cis 4-hydroxymelein (9), and (2S,3S,6R,7R,9S,10S)-humulene triepoxide (10) were isolated from CCE. The structures of isolated compounds were determined by spectroscopic analyses of 1D and 2D NMR, IR, and MS spectra. The most active compound was hydroquinone (7) with IC₅₀ = 0.37 ± 1.37 μg/mL as a substantial active principle of CCE. In addition, the new phenylpropanoid 2 (IC₅₀ = 27.8 ± 0.34 μg/mL) also showed significant activity against L. major compared to the positive control miltefosine (IC₅₀ = 7.47 ± 0.3 μg/mL). The activities of the isolated compounds were also evaluated against Plasmodium falciparum, Trypanosoma brucei gambisense and Trypanosoma brucei rhodeisense. Interestingly, compound 2 was selectively active against trypanosomes with potent activity. To the best of our knowledge, this is the first report on the bioactive “unnatural” natural products from the crude extract of A. galanga (L.) by chemical conversion and on its activities against causal pathogens of leishmaniasis, trypanosomiasis, and malaria.     

Phytoconstituents and pharmacological activities of cyanobacterium Fischerella ambigua

Cyanobacteria, also known as blue-green algae, are known to be a rich source of secondary metabolites with diverse chemical structures and biological activities. Over 1100 natural constituents of cyanobacterial origin have been reported in the literature. These include various natural biologically active constituents with antimicrobial, antiviral, immunosuppressive, and anticancer activities. Terrestrial cyanobacteria of genus Fischerella (Family Fischerellaceae), belonging to order Stigonematales have recently received enormous attention from the researchers due to the presence of vast array bioactive compounds. Fischerella species are filamentous cyanobacteria with creeping thallus and sheath in filaments. Several species within the genus are known to produce interesting bioactive constituents. Perhaps the best characterized are F. ambigua and F. muscicola, which have been reported to produce antibacterial, antifungal and antialgal isonitrile containing indole alkaloids, such as hapalindoles, ambiguine isonitriles, fischerindoles, and wetwitindolinones. Keeping in mind these resources, a detailed literature survey on a cultured, fresh water and terrestrial cyanobacterium Fischerella ambigua (N?g.) Gom. has been carried out. The current review describes the chemical constituents isolated from different extracts of Fischerella ambigua, as well as their biological activities.     

Synthesis and pharmacological evaluation of 9(10H)-acridone bearing 1,3,4-oxadiazole derivatives as antimicrobial agents

In the present study a new acridone derivatives were synthesized. The newly synthesized compounds were characterized by IR, NMR and C, H, N, S analyses. All newly synthesized compounds were screened for their antibacterial (Staphylococcus aureus, Streptococcus viridans and Escherichia coil) and antifungal (Gibberela, Cercospora arachidicola, Physolospora piricola and Fusarium oxysporum) studies. The results revealed that all synthesized compounds have a significant biological activity against the tested microorganisms.     

Antimicrobial activity-guided identification of compounds from the deciduous leaves of Malus doumeri by HPLC-ESI-QTOF-MS/MS

This paper intends to identify the antimicrobial activity compounds from the deciduous leaves of Malus doumeri (Dong Li Tea) by HPLC-ESI-QTOF-MS/MS. The ethanol extracts of Malus doumeri were partitioned into petroleum ether, dichloromethane, ethyl acetate, n-butanol and water fraction, respectively. The antimicrobial screening experiments showed that ethyl acetate fraction has a certain antibacterial activity by inhibition zone method in vitro. And then we used the HPLC-ESI-QTOF-MS/MS method to verify the identities of bioactive compounds. Finally, 41 compounds were determined and 11 of which were firstly reported in this plant. Notably, compounds (32, 34, 38) are new dihydrochalcones, and three chlorogenic acid analogues (10, 13, 17) may be potential antimicrobial active ingredient. Which is of great significance to the isolation of novel compounds and the discovery of new natural preservative candidates from the deciduous leaves of Malus doumeri.     

Synthesis of Some New Biologically Active Sulfur Compounds Containing Pyrazolo[3,4-d] pyrimidine Moiety

A novel series of the pyrazolo[3,4-d]pyrimidines having biologically active sulfur moieties 3-20 were prepared via reaction of 4-mercapto-1-phenyl-1 H -pyrazolo[3,4-d]pyrimidine 3 with different reagents. Identification of the new compounds was established by elemental analyses, IR, 1 H-NMR, and mass spectral data. Some of the obtained compounds showed the interesting antimicrobial activity comparable to antibiotic chloramphenicol as standard antibacterial agent and Terbinafin as a standard antifungal agent.     

Synthesis of Some New Heterocycles of Pharmaceutical Interest: Pyridinyl and Isoxazolyl Quinoxaline Derivatives

3‐(p‐Acetyl‐anilinomethyl)quinoxalin‐2(1H)‐one ( 3 ) was prepared by the reaction of 3‐bromomethyl‐quinoxalin‐2(1H)‐one ( 1 ) with p‐aminoacetophenone ( 2 ) in pyridine. Reaction of p‐acetylcompound ( 3 ) with aromatic aldehydes yield the corresponding chalcones ( 4a‐c ). Condensation of latter chalcones with malononitrile afforded cyanopyridines ( 5a‐c ). Also, the reaction of chalcones ( 4a‐c ) with hydroxylamine hydrochloride furnished isoxazoles ( 6a‐c ). The reaction of bromo compound ( 1 ) with p‐aminobenzophenone yield ( 8 ) which was condenced with hydrazine hydrate to get the corresponding hydrazone derivatives ( 9 ). Some of the synthesized compounds have been screened for their antimicrobial activity against various strains of bacteria and fungi.     

New insights about the electrochemical production of ozone

Ozone is a rather attractive oxidant, it is very efficient in the oxidation of pollutants and in the killing of pathogens and does not generate any hazardous waste during its use. Its generation has been constantly sought in an effective way, focusing on obtaining high concentrations of ozone at the lowest possible cost. Recently, electrochemical production of ozone show advantages over conventional corona discharge generation, since this technology do not need very high voltages, feeding oxygen or pure air or dissolving the ozone into wastewater to be treated. However, it is still at early development stage and there is still a long way to reach the high technology readiness levels needed to complete its value chain. Equipment considerations and operation conditions are the key points that need to be understood in order to increase efficiently. Recent novelties in the state of the art of research are summarized in this work.     

New α‐Tetralone Galloylglucosides from the Fresh Pericarps of Juglans sigillata

Three new α‐tetralone galloylglucosides, 1 – 3 , were isolated from the fresh pericarps of Juglans sigillata (Juglandaceae), together with six known compounds. The structures of the new compounds were determined as 1,2,3,4‐tetrahydro‐7‐hydroxy‐4‐oxonaphthalen‐1‐yl 6‐O‐[(3,4,5‐trihydroxyphenyl)carbonyl]‐β‐D ‐glucopyranoside ( 1 ), (1S)‐1,2,3,4‐tetrahydro‐8‐hydroxy‐4‐oxonaphthalen‐1‐yl 6‐O‐[(3,4,5‐trihydroxyphenyl)carbonyl]‐β‐D ‐glucopyranoside ( 2 ), and 1,2,3,4‐tetrahydro‐7,8‐dihydroxy‐4‐oxonaphthalen‐1‐yl 6‐O‐[(3,4,5‐trihydroxyphenyl)carbonyl]‐β‐D ‐glucopyranoside ( 3 ), respectively, on the basis of detailed spectroscopic analyses, and acidic and enzymatic hydrolysis. The antimicrobial activities of the isolated compounds 2, 4 , and 7 – 9 were evaluated.     

New Approaches for the Synthesis of Thiazoles and Their Fused Derivatives with Antimicrobial Activities

The 2‐ethoxy carbonyl methylene thiazol‐4‐one ( 3 ) reacts with acetophenone ( 4 ) to give the ethyl 2‐(4‐oxo‐4,5‐dihydro‐thiazol‐2‐yl)‐3‐phenyl‐2‐butenoate ( 5 ). The reactivity of the latter product towards aromatic aldehydes 6a‐d , cyanomethylene reagents 9a,b , aromatic aldehydes 13a‐d , phenylisothiocyanate ( 16 ), elemental sulfur and aromatic amines ( 20a‐c ) was studied to give arylidene, pyridine, thiophene and anilide derivatives. Some of the newly synthesized derivatives were used to synthesize fused derivatives. The antimicrobial activities of the newly synthesized products were tested in vitro for antimicrobial activity against two bacterial isolates, one saprophytic (Escherichia coli) and the other parasitic (Xanthomonas citri) and for antifungal activity against one saprophytic (Aspergillus fumigatus) and two phytopathogenics (Rhizoctonia solani and Fusarium oxysporum).     

Synthetic Utility of Enaminonitrile Moiety in Heterocyclic Synthesis: Synthesis of Some New Thienopyrimidines

The hitherto unknown 3-amino-5-bromo-4, 6-dimethylthieno [2, 3-b] pyridine-2-carbonitrile ( 4 ) was condensed with p-anisaldehyde affording the Schiff base ( 5 ). Acylation of the thienopyridine derivative ( 4 ) using freshly distilled acetic anhydride gave a mixture of mono and diacetyl derivatives ( 6 ) and ( 7 ). Condensation of ( 4 ) with triethylorthoformate yielded the ethoxymethyleneamino derivative ( 8 ), which was treated with hydrazine hydrate to give the hydrazide derivative ( 9 ), which in turn was converted to a triazolopyrimidine derivative ( 10 ) upon treatment with freshly distilled acetic anhydride. Thiation of ( 4 ) with carbon disulfide afforded the pyrimidine dithione derivative ( 11 ), which was alkylated with ethyl iodide to give the di-s-ethylpyrimidine derivative ( 12 ).On the other hand, treatment of ( 4 ) with formamide yielded the aminopyrimidine derivative ( 13 ), whereas its treatment by formic acid produced the thienopyrimidinone derivative (1 4 ). Chlorination of (1 4 ) with a mixture of phosphorus pentachloride and phosphorus oxychloride gave the chloropyrimidine derivative ( 15 ), which in turn afforded the hydrazide derivative ( 9 ) upon treatment with hydrazine hydrate. Hydrazinolysis of ethyl-3-amino-5-bromo-4,6-dimethylthieno[2,3-b]pyridine-2-carboxylate ( 17 ) gave the hydrazino derivative ( 18 ), which in turn was converted to 8-bromo-7,9-dimethyl-3-formylaminopyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one ( 19 ) and 8-bromo-3-diacetylamino-2,7,9-trimethylpyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one ( 20 ) upon treatment with formic acid and freshly distilled acetic anhydride, respectively.     

Concise Synthesis and Antimicrobial Activities of New Substituted 5‐Isoxazolpenicillins

The synthesis of a series of new 5‐isoxazolpenicillins is described, which were obtained by coupling substituted isoxazoles with 6‐APA. Concise large‐scale synthesis of 3,5‐disubstituted isoxazoles by 1,3‐dipolar cycloaddition using copper(I) as catalyst was also investigated. Representative compounds were assayed for antimicrobial activities, showing satisfactory antimicrobial activities against Gram‐negative bacteria.     

New insights on the bridge carbon-carbon bond in propellanes: a theoretical study based on the analysis of the electron localization function

The nature of the bonding between bridgehead carbon atoms (Ca, Ca') as well as the ring strain in a family of 10 propellanes formed by three-, four-, or five-member rings: [1.1.1] (I), [2.1.1] (II), [3.1.1] (III), [2.2.1] (IV), [3.2.1] (V), [2.2.2] (VI), [3.3.1] (VII), [3.2.2] (VIII), [3.3.2] (IX), and [3.3.3] (X) are studied by means of the electron localization function (ELF) at the DFT level (B3LYP/cc-pVTZ). The ELF analysis of smaller propellanes (I, II, and III) reveals the coexistence of two resonance forms: one with a nonbonding electron pair partially delocalized between Ca and Ca' atoms outside the cage (ionic) and the other with a bridge bond between the same atoms (covalent). The weights of each form are calculated according to the ELF-basin populations, yielding 94, 88, and 53% for the ionic structure of I, II, and III, respectively, while larger propellanes (IV-X) present only the covalent form. The question of the s-character of the bridge bond is addressed by dissecting the bridge-bond ELF basin into the molecular orbital contributions. Finally, sigma-aromaticity associated to surface electron delocalization has been analyzed by means of nucleus-independent chemical shift (NICS) calculations. The results point out that the stability of the fused ring structure of propellanes I, II, and III, can be assigned to the remarkable sigma-aromaticity of the involved three-member rings.     

A New Caffeoylquiniclactone, Neochlorgeniclatone from the Leaves of Betula platyphylla Suk.

Betula platyphylla Suk., whose bark and juice are used as anti-inflammatory and cough relieving agent1, is widespread in China. Previous investigations of this plant have led to the isolation of various compounds2,3. We herein report structural elucidation of a new caffeoylquiniclactone, named neochlorgeniclatone (1) isolated from the leaves of Betula platyphylla Suk..Compound 1 was obtained as white powder (EtOAc). The EI-MS gave ion fragments at m/z 336 [M]+, 163 [caffeoyl]+, which indi…     

Synthesis,Characterization and Antimicrobial Activity of a New Aromatic Sulfonyl Hydrazone Derivative and Its Transition Metal Complexes

In this study, benzenesulfonicacid‐1‐methylhydrazide (bsmh) derivatives such as 2‐hydroxy‐1‐naphtaldehydebenzenesulfonylhydrazone (Hnafbsmh) and its Ni(II), Pd(II), Pt(II), Cu(II), Co(II) complexes were synthesized. The structures of these complexes were investigated using elemental analyses (FT‐IR, LC‐MS, UV‐VIS), magnetic susceptibility and conductivity measurement techniques. The complexes were found to have general compositions [ML₂]. All the synthesized complexes were evaluated in vitro as antimicrobial agents against representative strains of six gram‐positive and four gram‐negative bacteria and as an antifungal agent by disc diffusion methods. All the bacteria and fungi studied were screened against some commercial antibiotics to compare them with our chemical's zone diameters.